Where is iodine used? What is iodine made from? Processing of natural iodine accumulators
Iodine- is included in the periodic table of Mendeleev and belongs to the group of halogens. It would be correct to call the element iodine from the Latin word Iodum. It is a black-gray crystals with a sheen of purple metallic hue (see photo). By the way, the ancient Greek name of the element is translated as “violet-like”. Iodine vapor has a pungent odor and a purple color.
Iodine was obtained in 1811 by the chemist and industrialist Courtois from seaweed by heating in concentrated sulfuric acid. A few years later, the famous Gay-Lussac explored Chemical properties element.
Iodine is very scattered in nature and due to this it is present almost anywhere in our planet. In free form in the form of minerals, this is a very rare substance, mainly deposits are developed in Japan and Chile. It is also industrially obtained from oil drilling waters, seaweed, saltpeter.
The iodine molecule is chemically very active and is a strong oxidizing agent.
A large mass of iodine is contained in sea water - in the process geological processes, iodine was gradually washed away from the surface of the earth's crust under the influence of ice, snow, rains and was carried away by rivers to the seas. Much of it is found in chernozem soils and peat bogs. But the mountainous areas, on the contrary, are very depleted in iodine, again due to the large amount of precipitation.
The action of iodine and its biological role
The action of a macroelement is vital for a living organism. Iodine enters the human blood with food and almost the entire amount is absorbed in the small intestine, from where it enters the blood and thyroid gland. It is also possible to receive a certain amount with the inhaled air and through the skin.
Iodine refers to biotic elements, i.e. to those affecting life:
- Thyroid gland - speeds up the metabolism, iodine supplies through reactions in the gland into the blood the necessary organic compounds and hormones that affect the level of metabolic intensity, oxidation processes and heat production.
- Nervous system - due to the action of the element, the growth of healthy cells is enhanced nervous system, due to which excessive irritability disappears and the emotional background becomes stable.
- The development and growth of the child - in the presence of iodine, protein synthesis occurs and metabolic processes in muscle tissues are accelerated, which leads to an increase in physical endurance, and it also has a positive effect on mental abilities.
- Lipid metabolism - a macronutrient stimulates metabolism in the subcutaneous fat layer, and thus fights obesity and its unpleasant manifestation - cellulite.
- Carbohydrate metabolism - through the work of the thyroid gland, iodine has an effect on the absorption of carbohydrates by the intestines.
- Strong immunity - the use of the element allows the body to actively resist colds and viral diseases.
Iodine also promotes the formation of phagocytes - cells in the blood that destroy harmful microorganisms. But in all the actions of iodine, the thyroid gland is involved, in which it accumulates. It is by passing through it that pathogenic organisms lose their strength.
Main biological significance iodine as a macronutrient, medicine associates with endemic goiter, which occurs due to iodine deficiency. This disease is found mainly in the mountainous regions of all continents. It is promoted by a lack of cobalt and an excess of manganese, as well as an unbalanced diet, when there is an excess of carbohydrates and fats with a lack of proteins and vitamins. Treatment among the population will make sense only with an integrated approach. It is necessary to carry out prevention in combination with the optimization of the composition environment and improvement of sanitary and hygienic living and working conditions.
Iodine in the history of medicine
Even thousands of years before scientific discovery element, people learned how to use it correctly. Here are some facts from history:
- already 5 thousand years ago in China, goiter was cured with the help of seaweed, and later recipes for treatment with extracts from the thyroid glands of animals (deer and pigs) were described;
- around the same time, the Sumerians were looking for magic grass in the coastal northern regions, the description of which was lost, and later there was information about the treatment of goiter with kelp or seaweed, and this was done at the state level;
- about 3000 years ago, the same Chinese discovered that the disease appeared more often in areas with mountainous terrain and with bad quality drinking water, the Romans discovered this fact a millennium later;
- in Europe, the earliest artistic depiction of a goiter is dated 1215, while among the Indians, the third millennium BC. The paintings depict a man with a goiter around his neck and a rattle called the "fool's scepter", which was an indication of dementia;
- in the Renaissance, goiter was considered an attribute of beauty, which may have been the result of the same dementia among the legislators of "fashion";
- the first mention of the term "thyroid gland" was used by the Englishman Thomas Wharton in the middle of the 17th century, and the word "cretin" - in 1754 in Diderot's Encyclopedia.
As you can see, the relationship between goiter and a decrease in the level of mental abilities was discovered relatively recently. Only in the middle of the 18th century did Denis Diderot describe the word "cretin" as weak-minded, deaf, ugly and with a goiter to the waist. And Napoleon drew attention to the fact that the presence of this disease in recruits initially makes them unfit for service. This theory was scientifically confirmed in 1896 by the biochemist E. Bauman.
Daily norm (need for an adult, for children, as well as for pregnant women)
The daily norm of a macronutrient depends on the body and the age of the person. For example, for an adult, the norm is about 150-300 mcg. children school age about 120 mcg per day is required, and children preschool age- 50-90 mcg.
It is quite easy to determine the norm from the calculation that our body requires 2-4 mcg / 1 kg of body weight. It should be borne in mind that not all iodine accumulates in organs and tissues, the excess is excreted in urine and saliva. That is, the iron will take exactly the amount that it needs. This is good only in the case of a healthy, efficient organ. If there are violations of the thyroid gland, then a medical adjustment of the daily norm is necessary.
Pregnant women and women during breastfeeding, children and adolescents need an increased dose of the element. But be sure to get a recommendation from your doctor.
It has been noted that the situation in the post-Soviet space is close to catastrophic. Because the real consumption of iodine is about 50-80 mcg, which is three times less than required.
An interesting fact: depending on the change of seasons, the level of iodine concentration in the blood also changes. In autumn, it begins to decline, and from March it rises to a maximum in June. The amplitude of oscillations is insignificant, but science has not yet explained it.
Lack (deficiency) of iodine in the body - what are the symptoms?
Deficiency of the macronutrient iodine, according to statistics, is widespread throughout the planet, and about a third of the entire population is at risk of iodine deficiency.
Iodine is part of the main thyroid hormones (about 60-65%), which, in turn, take part in metabolic processes, affect:
- mental development;
- growth of bone tissue;
- protein synthesis;
- breakdown of cholesterol and fats;
- stimulation of myelogenesis.
Iodine deficiency can lead to problems during pregnancy: congenital genetic abnormalities, stillbirth, cretinism. Therefore, it is necessary to monitor the level of iodine throughout the life of a person. With its lack, a child can be born with increased body weight and jaundice, which leads to swelling and late healing of the umbilical residue. The hairline is very weak and often affected by seborrhea. There may be a delay in the eruption of milk, and subsequently, permanent teeth. Limb deformity occurs. Functional murmurs are heard on auscultation of the heart. Intestinal disorders occur. Such babies may begin to sit and walk late.
Iodine deficiency can be fraught with mental retardation and at an older age, memory, motor skills, perception suffer, they often suffer from colds, as a result of which it is difficult for them to concentrate and academic performance falls. There may also be a violation of physical, sexual and neuropsychiatric development.
It is possible to achieve results in correcting iodine deficiency only by starting complex therapy from birth and continuing prevention throughout life. This is usually due to the fact that iodine is not able to accumulate in the body, and comes exclusively from food. And its presence in the body is vital, so negligence is unacceptable.
For an infant, the source of the element is breast milk, but only if the mother takes the required amount. With artificial feeding, the dosage must be carefully maintained.
Chronic deficiency is evident in the truest sense of the word. Outwardly, it is expressed in an increase in the thyroid gland (endemic gland). This disease is also called Basedow's disease. Its essence lies in the fact that in case of a lack of iodine, iron increases in size in order to avoid insufficient production of hormones. Thyrotoxicosis develops (lack of those same hormones), the symptoms of which are increased heart rate, nervousness, weight loss, sweating, and restless sleep.
Also, the influence of an insufficient amount of the element also affects the general condition of the body and the appearance of a person: weakness, drowsiness, hearing and memory impairment, pallor and dry skin, hair problems, shortness of breath.
A folk remedy for checking for iodine deficiency is to apply a mesh with an alcohol solution to the skin. If it quickly disappears, then measures must be taken, but if the drawing does not disappear within a day, then everything is in order with the presence of the element, although you should not dwell on this and continue prevention. But doctors do not trust this method and use a urine or blood test. They believe that when applied to the skin, iodine can only have an irritating effect, causing blood flow and expansion of skin capillaries.
Today, iodine deficiency is the most common disease spread by non-infectious means, which leads to the mental retardation of the entire nation. This disease is becoming an "epidemic" and control in particularly affected countries should take place at the level of legislation.
According to WHO statistics, about 200 million people are considered affected, and almost a billion are at risk.
Signs of excess iodine and poisoning with it
An excess of iodine in the body can still exist, despite the global deficiency of the element as a whole. It can be caused by a violation of iodine metabolism and its excessive intake. An excess of this chemical may cause poisoning, tk. high concentration is toxic. Workers of enterprises with increased harmfulness, where iodine is released in the form of steam, are exposed to such poisoning.
The toxic effect of the element can lead to a violation general condition body (muscle weakness, sweating, diarrhea and weight loss), and with chronic action, pain in the stomach, vomiting, lacrimation, tinnitus, dizziness may appear. Depigmentation of the skin and hair occurs, which causes premature graying.
What food sources does it contain?
The consumption of iodine occurs mainly with foods of plant and animal origin. But it should be borne in mind that the content of the element is due to the state of the soil on which they are grown. The most saturated areas are located in areas close to the seas or oceans, and the poorest are mountainous areas due to leaching from the soil by precipitation. And it has been noticed that the inhabitants of cities suffer less from the lack than the rural ones. The reason for this is the use by the townspeople of a large assortment of imported products.
In addition to iodine-rich seafood (seaweed, fish, shrimp, etc.), you should eat radishes, carrots, tomatoes, potatoes, cabbage, currants, strawberries, eggs, onions. The element is also found in milk, beans, meat and buckwheat.
But the use of soy products doubles the need for a macronutrient, because. they (products) cause an increase in the volume of the thyroid gland.
High-quality seafood is very expensive, therefore, in order to replenish the balance of iodine in the body, one has to limit oneself to the use of sea salt. But at the same time, many do not take into account the fact that in the processes of heat treatment of a given product, the previously indicated chemical element practically does not remain in it. When using a special salt saturated with iodine, the value is short-lived, for the reason that the element “evaporates” from an open pack due to the volatile properties of this substance. Although such salt in our conditions is the most effective and cheapest remedy. However, it is necessary to add it to food only before use, and not during cooking.
You can not use an alcohol solution of iodine to compensate for iodine deficiency, because. it is only suitable for external use and contains high concentrations that can cause poisoning with this substance.
Medical preparations of iodine are produced in the form of sodium and potassium salts, Lugol's solution, infusions and vitamin preparations. However, they can cause some allergic reactions.
Indications for appointment
The indications for the appointment of a macronutrient are quite extensive, but all are associated with the stable functioning of the thyroid gland:
Everyone has ever used an alcohol solution of iodine, some are familiar with it from chemistry lessons. Someone faced a lack of iodine in the body, and someone confuses it with brilliant green. In this article, we have collected answers to the most frequently asked questions about iodine, we hope it will be useful!
When and by whom was iodine discovered
The chemical element "Iodine" was included in the periodic table in 1871.Like many chemical elements, iodine was discovered by accident in 1811 by the Frenchman Bernard Courtois while obtaining saltpeter from seaweed. As a chemical element, the substance was named "iodine" two years later, and officially entered into the periodic table in 1871.
Where and how is iodine obtained?
In its pure form (free form), iodine is extremely rare - mainly in Japan and Chile. The main production is made from seaweed (5 kg are obtained from 1 ton of dry kelp), sea water (up to 30 mg per ton of water) or from oil drilling waters (up to 70 mg per ton of water). There is a method for obtaining technical iodine from saltpeter and ash production waste, but the content of the substance in the source materials is not more than 0.4%.
The method of obtaining iodine has two directions.
- Seaweed ash is mixed with concentrated sulfuric acid and heated. After evaporation of the moisture, iodine is obtained.
- Iodine in liquids (sea or lake salt water, petroleum water) is bound with starch, or silver and copper salts, or kerosene (an outdated method, as it is expensive) into insoluble compounds, and then the water is evaporated. Later they began to use the coal method for extracting iodine.
How iodine affects the human body
Iodine and its derivatives are part of the hormones that affect metabolism human body, its growth and development, so the average person needs to consume up to 0.15 mg of iodine daily. Lack of iodine or its deficiency in the diet leads to thyroid diseases and the development of endemic goiter, hypothyroidism and cretinism.
An indicator of iodine deficiency in the body is fatigue and depressed mood, headache and the so-called "natural laziness", irritability and nervousness, weakening of memory and intelligence. There is arrhythmia, high blood pressure and a drop in the level of hemoglobin in the blood. Very toxic - 3 g of the substance is a lethal dose for any living organism.
In large quantities causes damage to the cardiovascular system, kidneys and pulmonary edema; there is a cough and a runny nose, lacrimation and pain in the eyes (if it gets on the mucous membrane); general weakness and fever, vomiting and diarrhea, increased heart rate and pain in the heart.
How to replenish iodine in the body?
- The main source of natural iodine is seafood, but extracted as far as possible from the coast: in the coastal strips, iodine is washed out of the soil, and its content in products is negligible. Eat seafood - this can restore the content of the substance in the body to a certain extent.
- You can artificially add iodine to edible salt, eat foods containing this trace element - sunflower oil, nutritional supplements.
- Pharmacies sell tablets with a high content of iodine - relatively harmless drugs (for example, iodine-active, antistrumine).
- A lot of iodine is found in persimmons and walnuts.
Where is iodine found?
Iodine is present almost everywhere. The highest content of iodine is in products of marine origin, in sea water itself and in salty lake water.
In free form - as a mineral - iodine is present in the thermal springs of volcanoes and natural iodides (lautarite, iodobromite, embolite, myersite). It is found in oil drilling waters, sodium nitrate solutions, saltpeter and potash liquors.
What foods contain iodine
In seafood: fish (cod and halibut) and fish oil, crustaceans and mollusks (scallops, crabs, shrimp, squid, oysters, mussels), seaweed. This is followed by dairy products and chicken eggs, feijoa and persimmon, sweet peppers, walnut peel and kernels, black grapes, cereals (buckwheat, corn, wheat, millet), river fish and red beans. Iodine is found in orange and red juices.
There is even less iodine in soy products (milk, sauce, tofu), onions, garlic, beets, potatoes, carrots, beans, strawberries (about 40-100 times less than in seaweed), but it is.
What foods do not contain iodine
Iodine is not found in baked goods (homemade) using regular iodine-free salt, peeled potatoes, unsalted vegetables (raw and frozen), peanuts, almonds, and egg whites. There is practically no iodine in cereals, poor in natural salts; pasta, cocoa powder, white raisins and dark chocolate. This applies to vegetable oils, including soybean.
Almost all known seasonings in dried form (black pepper, herbs) also do not have iodine-containing components - iodine is on outdoors quickly decomposes (volatilizes), which is why iodized salt is usable for only 2 months (if the pack is open).
Carbonated drinks - Coca Cola and its derivatives, wine, black coffee, beer, lemonade - all this also does not contain iodine.
Linen fabrics:
Option 1. Cover the stain with baking soda, pour vinegar on top and leave for 12 hours, and then wash in warm clean water.
Option 2. Dissolve a teaspoon of ammonia in 0.5 liters of water, and wipe the stain with the resulting solution. Next, wash in warm soapy water.
Option 3. A thick gruel is made from starch in water, applied to the stain and the stain is expected to turn blue. If necessary, repeat again, and wash the product in warm soapy water.
Option 4. Rub the stain with raw potatoes and wash the item in warm soapy water.
Option 5. You can wipe the stain with liquid ascorbic acid (or dissolve the tablet in water), and then wash it in soap and water.
Woolen, cotton and silk fabrics:
The stain should be wiped with a hyposulfite solution (a teaspoon per glass of water) and washed in warm water. You can wipe the stain with ammonia and wash in the usual way.
How to wash iodine from the skin
There are several options:
- Olive oil or a fat cream is applied to the skin, which will absorb iodine. After an hour, the iodine is washed off with a body sponge and soap.
- They take a bath with sea salt, and at the end they use a washcloth and baby (household - in extreme cases) soap.
- You can use a scrub instead of a washcloth for delicate skin, and massage the spot with a stain. After that, you can lubricate the skin with a nourishing cream or milk.
- You can apply cotton wool with alcohol, moonshine or vodka for 5 minutes to the stain, and then rub it. The procedure can be repeated several times.
- Removes iodine stains by hand washing things or a regular bath with powder or lemon juice.
How to gargle with iodine
The method is quite simple - you need to add a few drops of iodine to a glass of warm water until a light brown solution is obtained. But the effect will be better and stronger if you add a teaspoon of soda and table salt to the water. The method has proven itself in the treatment of purulent tonsillitis and chronic tonsillitis. The procedure can be repeated 3-4 times a day (with purulent tonsillitis - every 4 hours) for 4 days.
An alcoholic solution of iodine cannot be used to lubricate the throat with angina, such as Iodinol. Otherwise, you will simply burn the mucous membrane.
How to make an iodine grid, how often can you make an iodine grid
You need to take a thin stick with cotton wool, moisten it in a 5% alcohol solution of iodine and draw on the skin intersecting horizontal and vertical stripes in the form of a plate with 1x1cm squares. This is the ideal geometry for the uniform distribution of iodine: it is absorbed quickly and efficiently.
It can be done within a week only two or three times for any diseases.
At what age can you smear with iodine
Doctors do not recommend smearing skin with iodine even in adolescence - iodine burns the skin. But the iodine grid (once) can be done from the age of five. But there is a more "advanced" and safer version of iodine that can be used and.
Why is iodine in the periodic table, but no brilliant green?
Because brilliant green is a synthetic antiseptic, an aniline dye. The periodic table includes only chemical elements and compounds that exist in nature in their pure form.
Iodized salt should be substituted for salt ordinary people living in regions of iodine deficiency.
Because this salt helps to restore balance in case of iodine deficiency in the human body, it is the prevention of iodine deficiency diseases in children, pregnant and lactating women, adolescents. Salt with iodine helps prevent the absorption of radioactive components of iodine by the thyroid gland and is a protection against radiation, inflammation and diseases.
How is iodized salt made?
Iodine is added in a certain concentration to sea or lake salt water, mixed with water and only then evaporated.
The horizon is getting better. Salt and iodine in the air.
Where can I get iodine in the air?
Iodine is a rather rare element: in earth's crust it is very small - only 0.00005%, which is four times less than arsenic, five times less than bromine. Iodine belongs to the halogens (in Greek hals - salt, genos - origin). Indeed, in nature, all halogens occur exclusively in the form of salts. But if the minerals of fluorine and chlorine are very common, then the own minerals of iodine (lautarite Ca(IO 3) 2, iodargyrite AgI) are extremely rare. Usually iodine occurs among other salts as an impurity. An example is natural sodium nitrate - Chilean nitrate, in which there is an admixture of sodium iodate NaIO 3. Deposits of Chilean saltpeter began to be developed in the early 19th century. After the rock was dissolved in hot water, the solution was filtered and cooled. At the same time, pure sodium nitrate precipitated, which was sold as a fertilizer. Iodine was extracted from the solution remaining after crystallization. In the 19th century, Chile became the main supplier of this rare element.
Sodium iodate is quite soluble in water: 9.5 g per 100 g of water at 25 ° C. Sodium iodide NaI dissolves much better: 184 g per 100 g of water! Iodine in rocks is most often in the form of easily soluble inorganic salts and therefore can be leached from them by groundwater. And then it gets into rivers, seas and oceans, where it accumulates by some organisms, including algae. For example, 1 kg of dried seaweed (kelp) contains 5 g of iodine, while 1 kg of sea water contains only 0.025 mg, that is, 200 thousand times less! It is not for nothing that in some countries iodine is still extracted from kelp, and the sea air (which Brodsky had in mind) has a special smell; sea salt also always has a little iodine. The winds that carry air masses from the ocean to the mainland also carry iodine. In coastal areas, the amount of iodine in 1 cu. m of air can reach 50 micrograms, while in continental and mountainous areas it is only 1 or even 0.2 micrograms.
Now iodine is extracted mainly from the waters of oil and gas fields, and the need for it is quite large. More than 15,000 tons of iodine are mined annually around the world.
Discovery and properties of iodine.
For the first time, iodine was obtained from the ashes of seaweed by the French chemist Bernard Courtois in 1811. Here is how he described the properties of the element he discovered: “The new substance precipitates in the form of a black powder, which turns into vapors of magnificent purple. These vapors condense in the form of brilliant crystalline plates with brilliance ... The amazing color of the vapors of the new substance makes it possible to distinguish it from all hitherto known substances ... ". Iodine got its name from the color of the vapors: in Greek, “iodes” means purple.
Courtois observed another unusual phenomenon: solid iodine did not melt when heated, but immediately turned into steam; this process is called sublimation. D.I. Mendeleev in his chemistry textbook describes this process as follows: “To purify iodine, it is sublimated ... iodine passes directly from the vapor into a crystalline state and sits in the cooled parts of the apparatus in the form of lamellar crystals that have a blackish-gray color and a metallic shine". But if iodine crystals are heated in a test tube quickly (or do not let iodine vapor escape), then at a temperature of 113 ° C, iodine will melt, turning into a black-violet liquid. This is explained by the fact that at the melting point the vapor pressure of iodine is high - about 100 mm of mercury (1.3 × 10 4 Pa). And if there is not enough of its vapor above the heated solid iodine, then it will evaporate faster than it will melt.
In its pure form, iodine is black-gray heavy (density 4.94 g / cm 3) crystals with a purple metallic sheen. Why is iodine tincture not purple? It turns out that in different solvents iodine has different colour: in water it is yellow, in gasoline, carbon tetrachloride CCl 4, many other so-called "inert" solvents it has a purple color - exactly the same as that of iodine vapor. A solution of iodine in benzene, alcohol and a number of other solvents has a brown-brown color (as in iodine tincture); in an aqueous solution of polyvinyl alcohol (-CH 2 -CH (OH) -) n iodine has a bright blue color (this solution is used in medicine as a disinfectant called "iodinol", they gargle, wash wounds). And here's what is curious: the reactivity of iodine in "multi-colored" solutions is not the same! So, in brown solutions, iodine is much more active than in purple ones. If copper powder or a sheet of thin copper foil is added to a 1% brown solution, it will become colorless in 1–2 minutes as a result of the reaction 2Cu + I 2 ® 2CuI. The violet solution will remain unchanged under these conditions for several tens of minutes. Calomel (Hg 2 Cl 2) decolorizes a brown solution in a few seconds, and violet in only two minutes. These experiments are explained by the fact that iodine molecules can interact with solvent molecules, forming complexes in which iodine is more active.
A blue color also appears when iodine interacts with starch. This can be verified by dropping iodine tincture on a slice of potato or on a piece of white bread. This reaction is so sensitive that with the help of iodine it is easy to detect starch on a fresh cut of a potato or in flour. Back in the 19th century. this reaction was used to convict unscrupulous merchants who added wheat flour to sour cream "for density". If a sample of such sour cream is dripped with iodine tincture, blue staining will immediately reveal fraud.
To remove the stain from iodine tincture, you must use a solution of sodium thiosulfate, which is used in photography and is sold in photographic stores (it is also called "fixer" and "hyposulfite"). Thiosulfate instantly reacts with iodine, completely discoloring it: I 2 + 2Na 2 S 2 O 3 ® 2NaI + Na 2 S 4 O 6. It is enough to wipe the skin or fabric stained with iodine with an aqueous solution of thiosulfate, as the yellow-brown spot will immediately disappear.
Iodine in the first aid kit.
Conscious ordinary person(not a chemist) the word "iodine" is associated with a bottle that is in the first aid kit. In fact, the vial contains not iodine, but iodine tincture - a 5% solution of iodine in a mixture of alcohol and water (potassium iodide is also added to the tincture; it is needed so that iodine dissolves better). Previously, iodoform (triiodomethane CHI 3), a disinfectant with an unpleasant odor, was also widely used in medicine. Preparations containing iodine have antibacterial and antifungal properties, they also have an anti-inflammatory effect; they are used externally for the disinfection of wounds, in the preparation of operations.
Iodine is poisonous. Even such a familiar iodine tincture, when inhaled, affects the upper respiratory tract, and when ingested, causes severe burns of the digestive tract. Prolonged administration of iodine into the body, as well as hypersensitivity to it, can cause a runny nose, urticaria, salivation and lacrimation, and acne.
Iodine in the body.
Here are the lines of another poet - Bella Akhmadulina:
...Either a strong spirit ordered to look for an outcome,
Is it a weakness of the thyroid gland
begging for bitter dainties of iodine?
Why does the thyroid gland need this “delicacy”?
As a rule, only the "light" elements that are in the first third of the periodic table participate in biochemical processes. Almost the only exception to this rule is iodine. A person contains about 20 to 50 mg of iodine, a significant part of which is concentrated in the thyroid gland (the rest of the iodine is in the blood plasma and muscles).
The thyroid gland was already known to ancient doctors who deservedly attributed to it important role in the body. In shape, it looks like a bow tie, i.e. consists of two lobes connected by an isthmus. The thyroid gland secretes hormones into the blood that have a very versatile effect on the body. Two of them contain iodine - this is thyroxine (T4) and triiodothyronine (T3). The thyroid gland regulates the development and growth of both individual organs and the whole organism as a whole, adjusts the speed of metabolic processes.
In food and drinking water, iodine is found in the form of hydroiodic acid salts - iodides, from which it is easily absorbed in the anterior sections of the small intestine. From the intestine, iodine passes into the blood plasma, from where it is eagerly absorbed by the thyroid gland. There it turns into the most important thyroid hormones for the body (from the Greek thyreoeides - thyroid). This process is complex. First, ions I - are enzymatically oxidized to I +. These cations react with the protein thyroglobulin, which contains many residues of the amino acid tyrosine. iodination occurs by the action of the enzyme iodinase benzene rings tyrosine with subsequent formation of thyroid hormones. Currently, they are obtained synthetically, and in structure and action they are no different from natural ones.
If the synthesis of thyroid hormones slows down, the person develops a goiter. The disease is caused by a lack of iodine in the soil, water and, consequently, in plants, animals and locally produced foods. Such a goiter is called endemic, i.e. characteristic of the area (from the Greek endemos - local). Areas with iodine deficiency are quite common. As a rule, these are areas remote from the ocean or fenced off from sea winds by mountains. Thus, a significant part of the soil the globe poor in iodine, respectively, poor in iodine foods. In Russia, iodine deficiency occurs in mountainous areas; extremely pronounced iodine deficiency was detected in the Republic of Tuva, as well as in Transbaikalia. There is not enough of it in the Urals, the Upper Volga, Far East, Mari and Chuvash Republics. Not everything is safe with iodine in a number of central regions - Tula, Bryansk, Kaluga, Oryol and other regions. In drinking water, plants and animals in these areas, the iodine content is reduced. The thyroid gland, as if compensating for the insufficient intake of iodine, grows - sometimes to such a size that the neck is deformed, blood vessels, nerves, and even the bronchi and esophagus are compressed. Endemic goiter is easy to prevent if you make up for iodine deficiency in the body.
With a lack of iodine during pregnancy in the mother, as well as in the first period of a child's life, growth slows down, mental activity decreases, cretinism, deaf-mutism and other severe developmental abnormalities may develop. Timely diagnosis helps to avoid these misfortunes by simple introduction thyroxine.
Lack of iodine in adults leads to a decrease in heart rate and body temperature - patients feel chilly even in hot weather. Their immunity decreases, hair falls out, movement and even speech slow down, face and limbs swell, weakness, fatigue, drowsiness, memory impairment, indifference to the outside world are noted. The disease is also treated with T3 and T4 drugs. In this case, all of the above symptoms disappear.
Where to get iodine.
For the prevention of endemic goiter, iodine is introduced into food. The most common method is the iodization of table salt. Usually potassium iodide is introduced into it - about 25 mg per 1 kg. However, KI in humid warm air easily oxidizes to iodine, which volatilizes. This explains the short shelf life of such salt - only 6 months. Therefore, in recent times potassium iodide is replaced with KIO 3 iodate. In addition to table salt, iodine is added to a number of vitamin mixtures.
Iodized foods are not needed for those who consume enough iodine through food and water. The need for iodine for an adult depends little on gender and age and is approximately 150 mcg per day (however, it increases during pregnancy, increased growth, and cooling). Most foods contain very little iodine. For example, in bread and pasta it is usually less than 5 micrograms; in vegetables and fruits - from 1-2 mcg in apples, pears and black currants to 5 mcg in potatoes and up to 7-8 mcg in radishes and grapes; in chickens and beef - up to 7 mcg. And this is per 100 g of dry product, i.e. ash! Moreover, during long-term storage or heat treatment, from 20 to 60% of iodine is lost. But fish, especially sea fish, are rich in iodine: in herring and pink salmon it is 40-50 mcg, in cod, pollock and hake - up to 140-160 (also per 100 g of dry product). There is much more iodine in cod liver - up to 800 micrograms, but especially a lot of it in brown seaweed - "seaweed" (aka kelp) - it can contain up to 500,000 micrograms of iodine! In our country, kelp grows in the White, Barents, Japan and Okhotsk seas.
Also in Ancient China Seaweed has successfully treated thyroid disorders. In the coastal regions of China, there was a tradition - after giving birth, women were given seaweed. At the same time, mother's milk was full, and the child grew up healthy. In the 13th century there was even a decree issued obliging all citizens to eat seaweed to promote health. Oriental healers claim that after 40 years, seaweed products must be present in the diet of even healthy people. By eating kelp, some explain the longevity of the Japanese, as well as the fact that after the nuclear bombings of Hiroshima and Nagasaki, the number of deaths due to environmental pollution radioactive substances was relatively small.
Iodine and radiation.
In nature, iodine is represented by the only stable isotope 127 I.
Artificial radioactive isotopes of iodine - 125 I, 131 I, 132 I and others are widely used in biology and, especially, in medicine to determine the functional state of the thyroid gland and treat a number of its diseases. The use of radioactive iodine in diagnostics is associated with the ability of iodine to selectively accumulate in the thyroid gland; use for medicinal purposes is based on the ability of radiation of iodine radioisotopes to destroy diseased gland cells.
When the environment is contaminated with nuclear fission products, radioactive isotopes of iodine are quickly included in the biological cycle, eventually getting into milk and, consequently, into the human body. So, many residents of the areas affected by the nuclear explosion in Chernobyl received a hefty dose of radioactive iodine-131 (half-life of 8 days) and damaged the thyroid gland. Most of the patients were in areas where there was little natural iodine and the inhabitants were not protected by “ordinary iodine”. “Radioiodine” is especially dangerous for children, whose thyroid gland is 10 times smaller than that of adults and has greater radiosensitivity, which can lead to thyroid cancer.
To protect the thyroid gland from radioactive iodine, it is recommended to use ordinary iodine preparations (100–200 mg per dose), which “blocks” the thyroid gland from radioiodine entering it. Radioactive iodine not absorbed by the thyroid gland is almost completely and relatively quickly excreted in the urine. Fortunately, radioactive iodine does not live long, and after 2-3 months it almost completely decays.
Iodine in technology.
Significant amounts of mined iodine are used to produce high purity metals. This purification method is based on the so-called halogen cycle, discovered in 1915 by the American physical chemist Irving Langmuir (1881–1957). The essence of the halogen cycle can be explained by the example of a modern method for producing high-purity metallic titanium. When titanium powder is heated in a vacuum in the presence of iodine to a temperature above 400 o C, gaseous titanium (IV) iodide is formed. It is passed over a titanium wire heated by current up to 1100–1400 o C. With this high temperature TiI 4 cannot exist and decomposes into metallic titanium and iodine; pure titanium condenses on the wire in the form of beautiful crystals, and the released iodine can again react with titanium powder, turning it into volatile iodide. The iodide method can be used to purify various metals - copper, nickel, iron, chromium, zirconium, hafnium, vanadium, niobium, tantalum, etc.
The same cycle is carried out in halogen lamps. In conventional lamps, the efficiency is extremely low: in a burning light bulb, almost all the electricity is converted not into light, but into heat. To increase the light output of the lamp, it is necessary to increase the temperature of its spiral as much as possible. But at the same time, the lamp life is significantly reduced: the spiral in it quickly burns out. If, however, a very small amount of iodine (or bromine) is introduced into the lamp bulb, then as a result of the halogen cycle, the tungsten that has evaporated from the spiral and settled on the inner surface of the glass bulb is again transferred to the spiral. In such a lamp, it is possible to significantly - by hundreds of degrees - increase the temperature of the spiral, bringing it to 3000 ° C, which doubles the light output. A powerful halogen lamp looks like a midget compared to a conventional lamp of the same power. For example, a 300 watt halogen lamp has a diameter of less than 1.5 cm.
An increase in the temperature of the coil inevitably leads to a stronger heating of the flasks in halogen lamps. Plain glass cannot withstand such temperatures, so you have to place the spiral in a quartz glass tube. The first patents for halogen lamps were issued only in 1949, and their industrial production was established even later. The technical development of quartz lamps with a self-healing tungsten filament was carried out in 1959 by the General Electric Company. In such lamps, the balloon can heat up to 1200 ° C! Halogen lamps have excellent light characteristics, so these lamps, despite their high cost, are widely used wherever a powerful and compact light source is needed - in movie projectors, car headlights, etc.
Iodine compounds are also used to make it rain. Rain, like snow, begins with the formation of tiny ice crystals in the clouds from water vapor. Further, these embryonic crystals grow rapidly, become heavy and fall out in the form of precipitation, turning, depending on weather conditions, into snow, rain or hail. If the air is absolutely clean, ice germs can form only at very low temperatures (below -30 o C). In the presence of certain substances, however, ice nuclei form at a much higher temperature. This can cause artificial snowfall (or rain).
One of the best seeds is silver iodide; in its presence, ice crystals begin to grow already at –9 o C. It is essential that even the smallest particles of silver iodide with a size of only 10 nm (1 nm = 10–9 m) can “work”. For comparison: the radii of silver and iodine ions are 0.15 and 0.22 nm, respectively. Theoretically, 10 21 of these tiny particles can be obtained from a cubic AgI crystal with a size of only 1 cm, and it will not seem surprising that very little silver iodide is required to produce artificial rain. As American meteorologists have calculated, only 50 kg of AgI is enough to “seed” the entire atmosphere above the US surface (which is 9 million square kilometers)! At the same time, in 1 cu. m, more than 3.5 million centers of ice crystallization are formed. And to maintain the formation of ice nuclei, it is enough to consume only 0.5 kg of AgI per hour. Therefore, despite the relatively high cost of silver salts, the use of AgI to cause artificial rain is practically advantageous.
Sometimes it is required to perform the exact opposite task: to “disperse” the clouds, to prevent rain from pouring during some important event (for example, the Olympic Games). In this case, silver iodide must be sprayed into the clouds in advance, tens of kilometers from the venue of the celebration. Then the rain will fall on the forests and fields, and the city will have sunny, dry weather.
Ilya Leenson
History of iodine
The discovery of iodine dates back to 1811, the element was discovered by the Frenchman Bernard Courtois, who at one time was a specialist in soap and saltpeter making. One day, while experimenting with seaweed ash, a chemist noticed that a copper cauldron for evaporating ash is subject to rapid destruction. When ash vapors were mixed with sulfuric acid, vapors of a saturated violet color were formed, which, when precipitated, turned into shiny crystals of a dark “gasoline” color.
Two years later, Joseph Gay-Lussac and Humphry Davy began to study the resulting substance and named it iodine (from the Greek iodes, ioeides - violet, violet).
Iodine is a halogen, belongs to the reactive non-metals, an element of the 17th group of the V period periodic table chemical elements DI. Mendeleev, has atomic number 53, the accepted designation is I (Iodum).
Being in nature
Iodine is a rather rare element, but, oddly enough, it is present in nature almost everywhere, in any living organism, in sea water, soil, plant and animal products. Traditionally, seaweed provides the largest amount of natural iodine.
Physical and chemical properties
Iodine is a solid substance, in the form of crystals of dark purple or black-gray color, has a metallic luster and a specific smell. Vapors of iodine - violet, are formed when the microelement is heated, and when it is cooled, they turn into crystals without becoming liquid. To obtain liquid iodine, it must be heated under pressure.
Daily requirement for iodine
For the normal functioning of the thyroid gland, an adult needs 150-200 micrograms of iodine, adolescents, pregnant women and nursing mothers need to increase the amount of iodine entering the body daily to 400 micrograms per day.
The main sources of iodine:
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It must be remembered that during cooking, up to half of the amount of iodine is lost, as well as during long-term storage.
Useful properties of iodine and its effect on the body
Iodine is an active participant in oxidative processes that directly affect the stimulation of brain activity. Most of iodine in the human body is concentrated in the thyroid gland and plasma. Iodine contributes to the neutralization of unstable microbes, thereby reducing irritability and stress (calorizator). Also, iodine has the property to increase the elasticity of the walls of blood vessels.
Iodine will facilitate dieting by burning excess fat, promote proper growth, give more energy, improve mental alertness, make hair, nails, skin and teeth healthy.
Signs of iodine deficiency
Lack of iodine is usually observed in regions where there is not enough natural trace elements. Signs of iodine deficiency are increased fatigue and general weakness, frequent headaches, weight gain, noticeable memory impairment, as well as vision and hearing, conjunctivitis, dry mucous membranes and skin. Lack of iodine leads to disruption of the menstrual cycle in women and a decrease in sexual desire and activity of the male.
Signs of excess iodine
An excess of iodine is no less harmful than its deficiency. Iodine is a toxic trace element, and when working with it, you need to be extremely careful to avoid poisoning, which is characterized by severe pain in the stomach, vomiting and diarrhea. With an excess of iodine in the water, the following symptoms are noted: an allergic rash and rhinitis, increased sweating with a pungent odor, insomnia, increased salivation and swelling of the mucous membranes, tremors, and rapid heartbeat. The most common disease associated with an increased amount of iodine in the body is Graves' disease.
The use of iodine in life
Iodine is mainly used in medicine, in the form of an alcohol solution - to disinfect the skin, speed up the healing of wounds and injuries, and also as an anti-inflammatory agent (an iodine cell is drawn at the site of bruises or during a cough for warmth). With a diluted solution of iodine, gargle with colds.
Iodine has found application in forensics (fingerprints are detected with it), as a component for light sources, and in the production of batteries.
Iodine (a trivial (common) name is iodine; from other Greek ἰώδης - “violet (violet)”) - an element of the 17th group of the periodic table of chemical elements (according to the outdated classification - an element of the main subgroup of group VII), the fifth period, with atomic number 53. Denoted by the symbol I (lat. Iodum). Reactive non-metal, belongs to the group of halogens.
The simple substance iodine (CAS number: 7553-56-2) under normal conditions is black-gray crystals with a violet metallic luster, easily forms violet vapors with a pungent odor. The molecule of a substance is diatomic (formula I 2).
Story
iodine was discovered in 1811 by Courtois in the ashes of seaweed, and from 1815 Gay-Lussac began to consider it as a chemical element.
Name and designation
The name of the element was proposed by Gay-Lussac and comes from other Greek. ἰώδης, ιώο-ειδης (lit. "violet-like"), which is associated with the color of the steam, which was observed by the French chemist Bernard Courtois, heating the mother brine of seaweed ash with concentrated sulfuric acid. In medicine and biology, this element and simple substance is usually called iodine, for example, “iodine solution”, in accordance with the old version of the name that existed in chemical nomenclature until the middle of the 20th century.
In modern chemical nomenclature, the name iodine is used. The same position exists in some other languages, for example in German: the common Jod and the terminologically correct Iod. Simultaneously with the change in the name of the element in the 1950s by the International Union of General and Applied Chemistry, the element symbol J was changed to I.
Physical properties
iodine under normal conditions is a solid black-gray substance with a metallic luster and a specific odor. Vapors have a characteristic violet color, just like solutions in non-polar organic solvents, such as benzene, in contrast to a brown solution in polar alcohol. iodine at room temperature is a dark purple crystals with a faint luster. When heated at atmospheric pressure, it sublimates (sublimates), turning into a violet vapor; when cooled, iodine vapor crystallizes, bypassing the liquid state. This is used in practice to purify iodine from non-volatile impurities.
Chemical properties
Iodine belongs to the group of halogens.
It forms a number of acids: hydroiodic (HI), iodic (HIO), iodide (HIO 2), iodic (HIO 3), iodine (HIO 4).
Chemically, iodine is quite active, although to a lesser extent than chlorine and bromine.
1. With light heating, iodine interacts vigorously with metals, forming iodides:
Hg + I 2 = HgI 2
2. Iodine reacts with hydrogen only when heated and not completely, forming hydrogen iodine:
I 2 + H 2 \u003d 2HI
3. Atomic iodine is an oxidizing agent, less powerful than chlorine and bromine. Hydrogen sulfide H 2 S, Na 2 S 2 O 3 and other reducing agents reduce it to the I ion -:
I 2 + H 2 S \u003d S + 2HI
4. When dissolved in water, iodine partially reacts with it:
I 2 + H 2 O ↔ HI + HIO, pK c \u003d 15.99